At 38 weeks pregnant, a blood pressure reading of 140/90 mmHg or higher is considered high. This threshold applies whether you had normal blood pressure earlier in pregnancy or have been managing chronic hypertension. A reading of 160/110 mmHg or higher is classified as severe and requires immediate attention. Even a single elevated reading at this stage will prompt your care team to act quickly, since you’re close enough to your due date that delivery is often the safest path forward.
The Numbers That Matter
Blood pressure in pregnancy is measured the same way as outside of pregnancy: two numbers, systolic (top) over diastolic (bottom). Here’s how the ranges break down:
- Normal: Below 140/90 mmHg
- High (hypertension): 140/90 mmHg or above on two or more readings taken at least four hours apart
- Severe: 160/110 mmHg or above
A single high reading doesn’t automatically mean you have a hypertensive disorder. Your provider will typically recheck within four hours to confirm the reading before making a diagnosis. That said, if you hit the severe range (160 systolic or 110 diastolic, or both), that confirmation window tightens considerably.
Gestational Hypertension vs. Preeclampsia
If high blood pressure first appears after 20 weeks of pregnancy, it falls into one of two categories. Gestational hypertension means your blood pressure is elevated but your organs are functioning normally. Most women with gestational hypertension have only a small increase above the 140/90 threshold, and many go on to deliver without complications.
Preeclampsia is different. It’s diagnosed when high blood pressure comes with signs that your organs are under stress. The classic marker is protein in your urine (more than 300 mg in a 24-hour collection), but preeclampsia can also be diagnosed without protein if you have other findings: a drop in platelet count, rising liver enzymes, kidney problems, fluid in the lungs, or new severe headaches that don’t respond to medication. Preeclampsia can affect virtually every organ system, and at its most severe, it can cause seizures or a dangerous condition called HELLP syndrome, where red blood cells break down, the liver becomes inflamed, and platelet counts plummet.
The distinction matters because preeclampsia tends to escalate. At 38 weeks, a preeclampsia diagnosis almost always means delivery is recommended promptly rather than waiting.
Why 38 Weeks Is a Decision Point
International guidelines currently state that planned delivery may be offered starting at 37 weeks for gestational hypertension and 38 weeks for chronic hypertension. A large randomized trial called the WILL Trial specifically studied women with chronic or gestational hypertension and found that planned birth between 38 weeks and 38 weeks plus 3 days resulted in delivery about 6 days earlier than usual care, with no increase in complications for either mother or baby. The takeaway: at 38 weeks, your baby is full term, and the risks of continuing the pregnancy with elevated blood pressure generally outweigh the benefits of waiting.
This doesn’t mean every woman with a slightly elevated reading at 38 weeks will be induced immediately. If your blood pressure is in the mild range and there are no signs of preeclampsia, your provider may monitor you closely with weekly visits (or more frequently) and plan delivery within the next week or so. If your pressures are in the severe range or you have signs of organ involvement, delivery is typically recommended within 24 to 48 hours.
Warning Signs to Watch For
At 38 weeks, you should know the symptoms that suggest your blood pressure is causing problems beyond the numbers on the cuff. These include a severe headache that won’t go away, visual changes like blurriness or seeing spots, pain in your upper right abdomen (where your liver sits), sudden severe swelling, shortness of breath, and nausea or vomiting that feels different from typical pregnancy discomfort. Mental confusion or altered behavior can also signal that blood pressure is affecting the brain. Any of these symptoms warrants an emergency room visit, even if your last blood pressure reading was normal.
How to Monitor at Home
If your provider has asked you to track your blood pressure at home, technique matters more than you might think. Sit quietly for a full five minutes before taking your first reading. Place the cuff directly on your bare upper arm, not over clothing. Take two or three readings each time, waiting at least one minute between each one. Record all of them rather than just picking the lowest number.
Most providers recommend checking once in the early morning (within an hour of waking, before any medication) and once in the evening (at least an hour after dinner). Some will ask for more frequent checks, up to three or four times daily. The consistency of your readings over time gives your care team a much clearer picture than any single measurement. If any reading hits 160/110 or above, contact your provider right away rather than waiting to recheck later.
After Delivery Isn’t the Finish Line
Blood pressure problems don’t always resolve the moment your baby arrives. Postpartum preeclampsia can develop from 48 hours to 6 weeks after delivery, even in women who had normal blood pressure throughout pregnancy. The majority of delayed-onset cases show up within the first 7 to 10 days, and the most common symptom is a severe headache. This is why most hospitals check your blood pressure repeatedly in the days after birth, and why you should take any new headaches, vision changes, or swelling seriously during those first weeks at home.